原发性肝癌的中国分期与TNM分期对肝癌切除的预后价值的比较研究

目的探讨原发性肝癌中国分期与TNM分期对判断手术切除肝癌预后的意义。方法回顾性分析我院1986年1月至2000年12月对246例原发性肝癌患者行手术切除病例的临床资料,其中227例患者随访3年以上。生存率计算采用KaplanMeier法,Longrang比较生存曲线。结果全组术后1、3、5、7、10年无瘤生存率分别为55%、30%、25%、20%及18%。新分期Ⅰa、Ⅰb、Ⅱa、Ⅱb及Ⅲ期术后1、3、5、7、10年无瘤生存期各期间差异均有统计学意义,并与TNM分期有一定相关性。TNM分期Ⅰ、Ⅱ、Ⅲ及Ⅳ期术后1、3、5、7、10年无瘤生存期差异有统计学意义,然Ⅲ、Ⅳ期间比较统计学差异无统计学意义。结论肝癌中国分期由于兼顾肿瘤与宿主肝功能两方面因素,分期更加精确,在反映切除肝癌预后方面具有重要价值。     

青年女性肺腺癌预后影响因素分析

目的 探讨青年女性肺腺癌的临床病理学特征对预后的影响。方法 回顾性分析手术治疗的青年女性肺腺癌282例，用Kaplan-Meier法计算生存率，分析临床病理学特征与预后的关系，并且进行Cox回归比例风险模型多因素分析。结果 吸烟与非吸烟组5年生存率分别为20．0％与36．4％（P=0．021）；p-TNM各分期5年生存率分别为Ⅰ期65．7％（Ⅰa期66．1％、Ⅰ期60．5％）、Ⅱ期30．9％（Ⅱa期36．3％、Ⅱb期27．5％）、Ⅲ期11．4％（Ⅲa期12．3％、Ⅲb期6．8％）、Ⅳ期3．6％，各期间生存率差异有统计学意义（P〈0．001）；淋巴结转移个数〉3个与≤3个的5年生存率分别为19．1％与38．3％（P=0．006）；高、中、低分化的5年生存率为65．2％、29．5％、19．8％（P〈0．001）。吸烟、p-TNM分期、转移淋巴结个数及分化程度与预后密切相关。多因素分析中吸烟、p-TNM分期和分化程度是独立的预后因素，相对危险比（RR）分别为3．315、2．809、1．195。结论吸烟、p-TNM分期、转移淋巴结个数及分化程度与青年女性肺腺癌的预后关系密切，吸烟、p-TNM分期和分化程度是青年女性肺腺癌的独立预后因素。因此，应当积极控制青年人群的吸烟，彻底清扫淋巴结，这对于青年女性肺腺癌预后具有重要意义。     

中国原发性肝癌临床分期预测肝癌肝移植预后的临床研究

目的评价“中国原发性肝癌临床分期”对肝癌肝移植疗效的预测价值。方法对1993年4月至2003年1月我科59例采用肝移植治疗的肝癌病人临床资料进行回顾性分析,按中国原发性肝癌临床分期原则进行分期,比较各期间肝癌肝移植疗效。结果Ⅰb、Ⅱa、Ⅱb、Ⅲa和Ⅲb期移植术后1年生存率分别为83·33%、66·67%、50·00%、35·71%和16·67%,各期间术后累计生存率有统计学差异(P<0·01);Ⅰb~Ⅱb和Ⅲa~Ⅲb期移植术后1年生存率分别为66·67%和25·00%,2年生存率分别为45·71%和25·00%,两组间术后累计生存率有统计学差异(P<0·05)。结论中国原发性肝癌临床分期适用于肝癌肝移植术前分期。     

射频消融治疗肝脏恶性肿瘤803例分析

目的 总结射频消融治疗肝脏恶性肿瘤的疗效及影响因素。方法 从1999年8月至2007年2月共应用射频消融治疗肝脏恶性肿瘤803例,其中原发性肝癌672例,肝转移瘤131例;超声引导781例,CT引导8例,腹腔镜下9例,开腹直视下5例;射频消融结合经皮瘤内无水酒精注射术117例,射频消融结合经导管肝动脉化疗栓塞术108例。结果 803例肝脏恶性肿瘤射频消融治疗的病死率为0．25％,严重并发症发生率为0．37％,完全消融率为92．5％,局部复发率为13．8％,术后1、2、3、4、5年累积生存率分别为95．1％、85．6％、75．7％、60．7％、47．5％;672例原发性肝癌术后5年累积生存率分别为：Ⅰa期61．9％、Ⅱb期42．2％（P〈0．01）。结论 射频消融是肝脏恶性肿瘤安全、有效的治疗手段,肿瘤大小和分期是重要的影响因素。     

病理N3期胃癌310例预后分析

目的探讨UICC第7版TNM分期标准中病理N3（pN3）期胃癌患者的预后特征及预后影响因素。方法回顾性分析2000年1月至2006年12月间天津医科大学附属肿瘤医院收治的实施胃癌根治术或扩大根治术的310例pN3期胃癌患者的临床病理和随访资料,分别采用Logrank检验和Cox比例风险模型进行单因素和多因素预后分析。结果310例患者均获随访,随访时间为2～103（平均35．7）月,术后5年生存率为14．6％。其中pN3a期201例,pN3b期109例,5年生存率分别为16．8％和10．3％,差异有统计学意义（P=0．013）。单因素预后分析显示,肿瘤部位、Borrmann分型、pT分期、pN分期、淋巴结转移率及手术方式与患者预后有关（均P〈0．05）。多因素分析显示,浸润深度、手术方式及淋巴结转移率是影响预后的独立危险因素（均P〈0．01）,而pN分期并不是独立的预后影响因素（P=0．658）。按浸润深度对患者进行分层分析显示,对于210例pT4a期患者,pN3a和pN3b亚组5年生存率分别为16．1％和12．8％,差异有统计学意义（P=0．001）;但对于88例pT4b期患者,pN3a和pN,b亚组5年生存率的差异则无统计学意义（8．6％比3．1％,P=0．137）。结论pM期胃癌患者预后较差,肿瘤浸润深度和不同手术方式是影响其预后的重要因素,淋巴结转移率对判断pM期胃癌预后有重要意义。第7版TNM分期中pN3分期能较好反映患者的预后情况。     

pTNM分期预测肝癌肝移植疗效的临床研究

目的 评价pTNM分期对肝癌肝移植疗效的预测价值。方法 对1993年4月至2003年1月我科59例采用肝移植治疗的肝癌患者的临床资料进行回顾性分析，按pTNM分期原则进行临床分期，比较各期间肝癌肝移植的疗效。结果 pTNM分期中Ⅰ、Ⅱ、Ⅲa和Ⅳa期的肝癌肝移植术后1年生存率分别为66．67％、66．67％、40．91％和31．75％，2年生存率分别为66．67％、66．67％、21．29％和31．75％，各期间术后累计生存率无统计学差异。结论 pTNM分期并不适用于肝癌肝移植的术前分期。     

Ⅲ期结直肠癌分期分层及其临床意义探讨

目的 探讨结直肠癌新TNM分期系统的临床应用价值.方法 回顾性分析1997年11月至2002年7月诊治的192例Ⅲ期结直肠癌患者的临床病理资料,应用Log-rank检验和Cox比例风险模型分析Ⅲ期结直肠癌患者的预后因素.结果 选择根治性手术治疗的Ⅲ期结直肠癌患者192例,分为辅助化疗组和未化疗组.中位随访时间60个月,术后总5年生存率为51.0%.按AJCC第6版TNM分期标准进行分期后的5年生存率分别为ⅢA期77.8%、ⅢB期57.4%、ⅢC期33.3%,3组患者生存率比较差异有统计学意义（χ^2=17.99,P＜0.01）.辅助化疗组125例,未化疗组67例,按新TNM分期分组,ⅢA＋ⅢB患者辅助化疗组5年生存率71.4%,未化疗组38.1%,两组差异有统计学意义（χ^2=15.77,P＜0.01）,而ⅢC患者化疗和未化疗组预后差异无统计学意义（39.1%vs.24.0%,χ^2=1.94,P＞0.05）.新TNM分期对指导不同亚期的Ⅲ期患者进行个体化综合治疗具有临床实用价值.单因素分析显示：患者性别、年龄、原发肿瘤部位、手术方式与预后无关,而新TNM分期、肿瘤分化程度、CEA水平,是否接受化疗等因素与预后相关.Cox多因素分析表明,新TNM分期是反映Ⅲ期结直肠癌预后最主要的独立指标.结论 新TNM分期对估计Ⅲ期结直肠癌的预后更为精确、合理.ⅢC患者不论是否化疗预后均不满意.     

跨肺裂型非小细胞肺癌患者手术预后分析及分期探讨

目的 探讨肿瘤跨肺裂侵犯对非小细胞肺癌( NSCLC)患者术后生存率的影响及合适的TNM分期.方法 回顾性分析上海肺科医院1997年至2007年接受根治性非小细胞肺癌手术病例临床和随访资料.将术后病理证实的非小细胞肺癌患者,按原发肿瘤是否跨肺裂侵犯,分别统计性别、年龄、吸烟史、肺功能、肿瘤部位、肿瘤大小、手术方式、淋巴结转移情况、TNM分期、病理类型,运用KaplanMeier生存分析和Cox比例风险模型,对预后因素进行分析.结果 跨肺裂侵犯(CF组)入组163例,肿瘤局限单肺叶(SL组)入组326例.根据IASLC最新推荐的第7版TNM非小细胞肺癌的分期,其中Ⅰa期10例(6.1％)、Ⅰb期79例(48.5％)、Ⅱa期5例(3.1％)、Ⅱb期44例(27.0％)、Ⅲa期25例(15.3％).CF组与SL组各期5年生存率分别为:Ⅰ期51％对63％,P＜0.05;Ⅱ期38％对36％,P=0.472、Ⅲa期27％对25％,P=0.422.按照T分期比较5年生存率,T2期CF组与SL组比较:35％对50％ (P =0.022);CF组T2期与SL组T3期比较35％对28％ (P =0.111).结论 Ⅰ期非小细胞肺癌患者伴跨肺裂侵犯邻近肺叶者,术后5年生存率较Ⅰ期不跨肺裂者低,为50％对63％,差异有统计学意义(P＜0.05);T2大小的肿瘤伴跨肺裂侵犯邻近肺叶者低于T2不跨肺裂者(P＜0.05),5年生存率与T3不跨肺裂组相近.肿瘤跨肺裂侵犯的T分期定义在当前分期系统中未明确提及,应当在以后的TNM分期中进一步修改.     

胃癌第7版TNM分期的临床应用

目的:分析胃癌第7版与第6版TNM分期之间的差别.方法:回顾性分析316例胃癌患者的临床病理资料,按第6版及第7版TNM分期标准分别进行分期,并分析各期5年生存率.结果:两版TNM分期在同一期之间生存差异无统计学意义(P>0.05);第7版Ⅰ期、Ⅱ期、Ⅲ期、Ⅳ期5年生存率分别为64.2%、49.9%、17.8%、0.0%,4个分期5年生存率差异有统计学意义(P<0.05);ⅢA期、ⅢB期、ⅢC期5年生存率分别为32.2%、28.2%、5.0%,3个亚期5年生存率差异具有统计学意义(P ＜0.05).结论:第7版TNM分期更加细化,并对患者预后做出科学的评估.对不同分期的患者进行个体化综合治疗,具有临床应用价值.     

男性乳癌38例临床分析

目的探讨男性乳癌的临床特点、诊治及预后。方法回顾性分析两院38例男性乳癌患者的临床资料。38例术前依据B超，钼钯摄影，细针穿刺等方法均确诊。行乳癌根治切除术3例，改良根治术27例，乳腺单纯切除术5例，放弃手术3例，术后单纯放疗4例，单纯内分泌治疗7例，放疗加化疗9例，化疗加内分泌治疗8例。结果年龄53-82（平均58．5）岁，TNM分期包括Ⅰ期13例，Ⅱ期19例，Ⅲ期4例，Ⅳ期2例。随访时间2个月至10年，平均73．8个月，随访率为73．6％（28／38）。死亡13例；其中8例死于复发及转移，5例死于心脑血管疾病。5，10年总体生存率分别为71．6％和55．3％；Ⅰ，Ⅱ期5，10年生存率分别为92．6％（25／27）和78．9％（15／19）；Ⅲ，Ⅳ期6例中随访4例，均于3年内死亡，无3年生存病例。结论男性乳癌病程长，预后差，生存率低，以改良根治术为主的综合治疗是目前对男性乳癌的主要治疗模式，预后与临床分期有一定的关系。     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.     

Intraoperative autotransfusion is associated with modest reduction of allogeneic transfusion in prosthetic hip surgery

Background: The efficacy of intraoperative salvage and washing of wound blood and the predictors of allogeneic red cell transfusions in prosthetic hip surgery are insufficiently known.
Methods: In 96 patients, undergoing primary or revision surgery, salvaged and washed red cells and, if necessary, allogeneic blood were used to keep haematocrit not lower than 33%. The bleeding of red cells during hospital stay was calculated from the red cell balance. The preoperative red cell reserve (millilitres of red cells in excess of a haematocrit of 33%) was estimated and the difference between this volume and the total bleeding of red cells was retrospectively used to classify patients with regard to the need for red cells. Stepwise regression analysis was used to define patient-related variables associated with allogeneic blood transfusion.
Results: Preoperative knowledge of the type of operation (primary, revision), the preoperative red cell reserve, and the body mass could predict roughly half of the need for banked blood (r²=0.45). Only one-third of the total bleeding of red cells was retransfused. For complete avoidance of allogeneic blood, autotransfusion was most effective in patients with a moderate need (0–4 u). However, 32% of such patients required allogeneic blood.
Conclusions: Autotransfusion has a limited efficacy to decrease the need for allogeneic blood, and other blood-saving methods should be added for this purpose. It is difficult to predict the need for allogeneic blood preoperatively.     

缺氧对肾小管上皮细胞分泌外泌体的影响

目的    观察缺氧对肾小管上皮细胞分泌外泌体的影响,探讨外泌体在缺氧致肾脏损伤中的作用及机制。 方法    （1）常氧（21% O₂）及缺氧（1% O₂）分别处理大鼠肾小管上皮细胞（NRK-52E）48 h,收集细胞上清液并使用高速梯度离心法分离外泌体。采用透射电镜、纳米示踪分析、Western印迹、蛋白浓度定量鉴定并比较两组外泌体的基本特性。（2）在共培养实验中,以不同浓度（1、10、50、100、300 mg/L）的常氧外泌体、缺氧外泌体分别干预脂多糖（LPS）诱导的大鼠原代腹腔巨噬细胞,使用实时荧光定量PCR与酶联免疫吸附试验（ELISA）法分别检测巨噬细胞白细胞介素6（IL-6）、肿瘤坏死因子α（TNF-α）、诱导型氮氧化物合酶（iNOS）水平;使用Western印迹法检测巨噬细胞磷酸化（p）STAT/STAT及细胞因子信号传导抑制蛋白1（SOCS1）的蛋白表达;最后,使用实时荧光定量PCR法检测常氧外泌体与缺氧外泌体中炎性反应相关微RNA（microRNA,miR）的表达差异。 结果    （1）离心得到的囊泡具有外泌体典型的结构,粒径小于150 nm,表达外泌体标志蛋白CD63,说明分离得到外泌体。缺氧对肾小管上皮细胞分泌的外泌体形态、粒径分布比例无明显影响,但提高了外泌体的分泌量。（2）缺氧外泌体相比于常氧外泌体促进了LPS诱导的M1型巨噬细胞IL-6、TNF-α、iNOS 的表达和分泌（均P＜0.01）,同时提高STAT的磷酸化水平并减少SOCS1的蛋白表达（均P＜0.01）;对炎性反应相关microRNA检测发现缺氧外泌体中miR-155、miR-27a表达量较常氧外泌体明显升高（P＜0.05）。 结论    缺氧可改变外泌体的生物学功能,表现为协同促进LPS诱导的M1型巨噬细胞的表型转化,这可能是慢性肾脏病微炎性反应状态持续的原因之一。     

In Vitro Function and Durability Assessment of a Novel Polyurethane Heart Valve Prosthesis

Abstract While flexible-leaflet, central-flow prosthetic heart valves promise relief from anticoagulation therapy, they continue to be restricted by inadequate durability. In consequence, a novel trileaflet valve, made entirely from polyurethane, has been developed. A batch of 6 consecutively manufactured polyurethane valves was subjected to hydrodynamic function and accelerated fatigue testing. Computerized data acquisition and control systems have been introduced to improve valve testing methodologies. In terms of hydrodynamic function, the polyurethane valve demonstrates transvalvular pressure gradients similar to those for a bioprosthetic valve (Carpentier-Edwards) and levels of retrograde flow significantly less than those for either the bioprosthetic valve or a bileaflet mechanical valve (St Jude Medical). The equivalent of 10 years of cycling without failure has been exceeded by all 6 polyurethane valves in accelerated fatigue tests with 2 valves remaining intact after 674 million cycles (equivalent to approximately 17 years) in continuing tests. Highspeed photography revealed considerable differences in leaflet motion between valves cycled at accelerated and physiological rates.     

Negative pressure ventilation vs. spontaneous assisted ventilation during rigid bronchoscopy: A controlled randomised trial

Background: Ventilation during interventional rigid bronchoscopy (IRB) under general anaesthesia (jet ventilation, positive pressure ventilation and spontaneous assisted ventilation) may offer some difficulties. This study compares the effectiveness during IRB of intermittent negative pressure ventilation (INPV) and spontaneous assisted ventilation (SAV). Methods: Thirty-eight patients submitted to IRB were randomised into two groups: SAV or INPV. All patients received a total intravenous anaesthesia; INPV patients were paralysed. Pre-and intra-operative arterial blood gases and O₂ flow through a rigid bronchoscope were assessed. The endoscopist applying a subjective score evaluated the operating conditions. Results: Patients of the INPV group, as compared to the SAV group, required a lower dosage of fentanyl (2.6 ± 1.8 (μg · kg^?1· h^?1 vs. 6.6 ± 4.8 μg · kg^?1· h^?1), a lower O₂ supply (3.3 ± 2.8 1/min vs. 11.6 ± 3.4 1/min), a shorter recovery time (5.4 ± 2.9 min vs. 9.8 ± 7.1 min) and no manually assisted ventilation (0 ± 0 vs. 1 ± 1.1 nd?/procedure). Intraoperative PaCO₂ was higher in the SAV (8.1 ± 1.3 kPa) than in the INPV group (5.0 ± 1.6 kPa) and intraoperative pH differed in the two groups (7.26 ± 0.05, SAV vs. 7.47 ± 0.08, INPV). Operating conditions, as assessed by a subjective score, were considered better with INPV than with SAV (4.9 vs. 4.3). Conclusions: As compared to SAV, INPV in paralysed patients during IRB reduces administration of opioids, shortens recovery time, prevents respiratory acidosis, excludes the need for manually assisted ventilation, reduces 02 need and affords optimal surgical conditions. INPV appears a safe, non-invasive and effective ventilatory management during IRB.